To test a system a large number of test cases are required to be generated and applied to the candidate system. In most of the methodologies the testing phase is placed at the end of development life cycle. The time constraint is more in this phase as compared to any other. Hence testing objective is to gain confidence in the product by verifying its reliability. For a reliable system, testing has to be performed more extensively on specific part(s) of the system, which is expected to be used more. In this paper, two additional parameters i.e. risk probability and associated impact expected in each subsystem is considered along with usages pattern. The test case priority is calculated on the basis of effective risk exposure of the even sequence.

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Usage Pattern Finite State Machine Failure State Risk Impact Risk Exposure Reliability